Solved Double scroll bar in Header No. 12 on computer - is this a glitch?

Hi,
I want to use Header No. 12. It looks perfect on mobile but on my computer, a double scroll bar appears on sub-menus and it moves the navigation slightly and looks weird (see screen capture attached). I am wondering - how can I fix this? is this a glitch or something that is "built into the design"? I feel that the double scrollbar is very weird on computer and distracting.
Many thanks
Jocelyne

 

Hi - thank you - I will test this afternoon and let you know how it turns out. This will eliminate the "double scrollbar". But what if I want to eliminate the single scrollbar? I will have just the right amount of menus and there will be no need to scroll.

May I ask you another question please? I am testing the vertical navigation, and for some reason, on my site it does not display correctly (see photos). I have enabled "output styles inline". What ma I doing wrong? I also went into the setting and specified that I want the vertical bar to be on the right. Gosh, I am certain the answer is right in front of my face but if you could point me in the right direction please, it would be super helpful and save me some time. I read the tutorials and I cannot find the answer to this.
Note - On my site, it is on the left. On your demo site, it is on the right and the content behind is dark. I would like it to be like your demo site. I am also fiddling around with Header No. 11 which I like a lot too, it will be one of these two. But Header No. 11 gives me same problem.